Now showing items 1-10 of 50
Zero-current transition PWM converters
(United States Patent and Trademark Office, 1996-01-23)
A zero-current transition pulse-width modulated (ZCT-PWM) d.c.-d.c. converter allows minority-carrier semiconductor devices such as, for example, bipolar junction transistors (BJTs), insulated gate bipolar transistors ...
On the evanescent fields and the causality of the focus wave modes
(AIP Publishing, 1995-08-01)
The diverging and converging field components of the source-free focus wave modes are studied within the framework of both the Whittaker and Weyl plane wave expansions, It is shown that, in the Weyl picture, the evanescent ...
Fiberoptic Temperature Sensors Based on Differential Spectral Transmittance Reflectivity And Multiplexed Sensing Systems
(Optical Society of America, 1995-07-01)
A concept for optical temperature sensing based on the differential spectral reflectivity/transmittance from a multilayer dielectric edge filter is described and demonstrated. Two wavelengths, lambda(1) and lambda(2), from ...
Fabry-Perot Fiber-Optic Sensors in Full-Scale Fatigue Testing on an F-15 Aircraft
(Optical Society of America, 1992-02-01)
We report results from fiber-optic-sensor field tests on an F-15 aircraft mounted within a full-scale test frame for the purpose of fatigue testing. Strain sensitivities of the order of 0.01 _m/m have been obtained.
Fast-Neutron Radiation Effects in A Silica-Core Optical-Fiber Studied By A Ccd-Camera Spectrometer
(Optical Society of America, 1994-05-01)
A simple CCD-camera spectrometer was deployed at the Los Alamos Spallation Radiation Effects Facility to characterize fast-neutron irradiation effects in several silica-based optical fibers over the wavelength range ...
Minimum Detectable Phase-Shift in Spectrum-Analysis Techniques Of Optical Interferometric Vibration Detection
(Optical Society of America, 1992-11-01)
The minimum detectable phase shift indicated in recent experimental reports of new linear spectrum-analysis techniques of optical interferometric vibration detection is established as the direct consequence of the 1/f noise ...
Characterization And Modeling Of Drift Noise in Fourier Transform Spectroscopy: Implications For Signal Processing And Detection Limits
(Optical Society of America, 1997-05-01)
A theoretical analysis of long-term drift noise in Fourier transform spectroscopy is presented. Theoretical predictions are confirmed by experiment. Fractional Brownian motion is employed as a stochastic process model for ...
Separation of Intrinsic and extrinsic Optical-Absorption in a Fluoride Glass
(AIP Publishing, 1991-07-01)
The contribution of impurity ions to the total optical absorption of a heavy metal fluoride glass has been determined at 532 and 1064 nm. Four ZrF4-BaF2-LaF3-AlF3-NaF glasses were prepared from various purity raw materials. ...
Measuring Microwave Shielding Effectiveness in Liquid-Nitrogen
(AIP Publishing, 1994-04-01)
A technique to distinguish between materials that can and cannot shield microwaves in liquid nitrogen was developed. The samples are placed in a modified X-band waveguide, which operates by the same ''insertion loss'' ...
Dynamics of the 5-EV optical-absorption in SIO2 glass
(AIP Publishing, 1993-06-01)
The optical absorption at 5 eV in SiO2 glass was observed, using laser calorimetry, to change reversibly depending on the intensity of UV light. The generation and bleaching of an absorption band at 5 eV by two- and ...